Intimacy between dogs and human beings has been in existence for thousands of years, but household dog keeping is not automated or intelligentized. For residents living in crowded cities, treatment of dog excrement is always one of the most important causes which restrict dog keeping or reduce dog keeping enjoyment. Most current town houses are delivered after decoration and most bathrooms are provided with close stools instead of squatting pans in advance, so that excrement of pet dog is particularly inconvenient to treat. On the other hand, full-automatic pet dog keeping cannot be realized if automatic discharge and clearing of excrement cannot be solved, so that care of a pet in a house becomes a problem once the owner goes out. Along with the increasing number of pet dog keeping people, care of pets left alone in the houses become a larger and larger problem once owners go out. For the public, more and more dogs stroll in cities and defecate randomly, which affects the appearance of cities. Therefore, people look forward to adding certain toilets special for dogs in cities on the premise of not changing the current blow-off lines in the cities.